Saddles on deck

[Geek99]

Help … the saddles decked out and  the action isn’t very low. I’ve set neck relief, intonation and checked nut height 

do I need a full pocket shim? It’s a squier p bass 

 

thanks 

[JohnH89]

Shim at bridge end of neck pocket . Business card or similar . 1/2 in or so wide and full width of pocket . Don't be led down the rabbit hole of full pocket shims , angled shims or horror stories of ski jump necks . Seriously , this has been done for years by major manufacturers with no ill effects . 

[Downunderwonder]

If end shims didn't cause ski jumps there would be no ski jumps. It's basic physics and materials science.

 

Wood creeps under constant load.

 

An end shim puts a constant bending force into the pocket length of the neck. Both sets of screws are yanking down and the support is the very end of the neck where it leaves the body, and the shim.

 

You can see the wear at the leaving end contacting the pocket on removed vintage necks.

 

Whether the neck ski jumps is down to the particular quality of the neck timber. That is why it happens to some and not all.

 

Full length shim = no problem. No escape from that maths.

[ped]

File down the saddle grooves with abrasive cord 👍🏼

[BigRedX]

Can someone on Basschat who has experienced ski-jump due to a non full-length shim on an instrument they own please post photos?

[Bassfinger]

I've never experienced it, but I torque the screws to manufacturers figures rather than simply eff'n tight like most folks are inclined to.

[BigRedX]

And even if it does occur it won't matter, as my understanding is that the wood "moves" to fill the gap. Necks that require a shim are very unlikely to to need "unshimming" in the future and if they did then surely the wood would move back to compensate. IMO it's all fuss over nothing.

[dmccombe7]

7 hours ago, JohnH89 said:

Shim at bridge end of neck pocket . Business card or similar . 1/2 in or so wide and full width of pocket . Don't be led down the rabbit hole of full pocket shims , angled shims or horror stories of ski jump necks . Seriously , this has been done for years by major manufacturers with no ill effects . 

That's what i did with my Sandberg MarloweDK that had exact same issue. I checked out so many youtube clips and asked advice on here as well as TB and this was the recommended repair by majority.

Worked a treat.

Dave

[spencer.b]

I had it on done on a p bass and it transformed it , think changing the break angle over the saddles made it way more resonant

[Norris]

I really don't think that a piece of card the thickness of a business card is going to cause a ski ramp in the heel of a guitar neck. You know they are made from pretty hard wood like maple, right?

 

Even if it did it would only affect frets that as a bass player you shouldn't be going near 😂

[Geek99]

I’ll get sone pictures tonight. There’s a tiny bit more drop to go but not enough to make things right.

[Geek99]

The neck and body aren’t from the same place so I expected a bit of trouble - 

probably neck pocket isn’t shallow enough and it’s original neck was thinner 

[dmccombe7]

When i was looking into this i did wonder why not just raise the full neck pocket with a flat shim of card or something rather than a wedge shim or even a narrow shim at back of neck pocket. ?

That way you get the additional height without any risk of neck warping ?

I appreciate the full flat shim would need to be thicker than a wedge shim because of angles but would it be a problem ?

Dave

[BigRedX]

1 hour ago, dmccombe7 said:

That way you get the additional height without any risk of neck warping ?

I appreciate the full flat shim would need to be thicker than a wedge shim because of angles but would it be a problem ?

 

I can't see how the neck is going to warp because of the presence of something less than a 1mm in thickness occupying about a quarter of the length of the neck pocket, unless there was a problem with the neck already in which case the shim is unlikely to be the catalyst.

 

I think one of the reasons why the small card shim is popular, is because it is completely invisible on most basses and guitars when installed, whereas a shim occupying the full area of the neck pocket will definitely be visible. I wonder how many people were completely unaware that their instrument had a shimmed neck until they had need to remove it? Also a full-size flat or angled shim will need to be exactly the same size as the neck pocket for it not to look terrible. You would be surprised by how thick a flat shim needs to be to have the same effect as small piece of card. An effective card shim can be made by anyone who can wield a pair of scissors. 

 

 

[ped]

This is why I think filing down the bridge saddle grooves is the best option, depending on how much rom you need of course. Saddles are cheap, it's easy to do, gives you more  adjustability and avoids any possibility of a ski jump. I've done it on a few instruments, and of course on neck thru basses it's the only choice anyway.

[neepheid]

Ski jump, while I am not disputing is a thing, am willing to bet is statistically speaking a rare occurrence.  Yet it gets spoken about like it's a foregone conclusion if you dare put a shim in there 🙄

 

There's a statistical chance that any mod can go wrong.  Roll the dice, or don't.  Punter's choice.

[BigRedX]

I'm disputing it. I've never encountered it in over 50 years of owning and playing guitars and basses

 

No-one has risen to my challenge earlier in the thread to produce actual evidence of their own instrument that exhibits this and furthermore has adversely affected the performance of said instrument.

 

I call bullshit.

[ped]

I think they are one of the reasons that Fender/G&L/Musicman stopped using the micro tilt mechanism. There are loads of examples out there. It takes a long time to happen so add a shim now and you may never live to see it cause an issue. 

[BigRedX]

I thought that the reason Fender abandoned the micro-tilt mechanism is that at the time (in the late 70s) they were incapable to building instruments to the tolerances required for it to work properly which was doubly compounded by the fact that their worn router templates were producing over-sized neck pockets. The net result was that as well as changing the vertical neck angle the micro-tilt was also pushing the neck sideways in the pocket.

 

In these days of CNC machined necks and bodies a shim shouldn't be necessary. Just cut the neck pocket and heel at the correct angles so that it is possible to get a suitably low action before the saddles bottom out. After all you only need to do the maths once and then the machines will create every instrument perfectly.

[Acebassmusic]

Here's a looooooong but interesting review of "ski jump problems" on Talkbass where a number of luthiers / repair people have tried to gather actual data and critically analyse all potential failure modes. The top and bottom I take from it is that it seems that the "ski jump" usually is the neck bending in the area around the 14th to 16th fret where the transition from the heel (rectangle profile) to the neck (circular profile) occurs due to the cross section of the neck (and therefore stiffness) is reduced by approx. 25%. We tend to think that the bend is in the heel area (at the last frets) as that is where the strings choke out. They also talk about the effect of adding shims and concluded that fitting a shim doesn't cause the ski-jump as the neck bending they identified was not in the heel area but slighly towards the nut in the transition area. YMMV

[tauzero]

Consider this: it's pretty easy to work out how thick a shim needs to be to raise/lower strings by a set amount, or how much strings will be raised/lowered by for a given thickness of shim. Basic geometry. You need to know the distance between where the shim will be in the neck pocket and the front of the neck pocket (the point about which the neck will pivot). The ratio of the neck length (nut to bridge) to this distance is the ratio of the string displacement to the shim thickness.

 

Worked example: neck length 865mm, distance between front of neck pocket and rear screw holes (where the shim is going) 45mm, shim 0.25mm thick. 865/45 = 19 approx. 19 * 0.25 = 4.75mm. This assumes a metal shim that doesn't flatten and that the area over which the shim sits doesn't deform, reducing the effective thickness of the shim.

 

So 0.25mm of shim is all that's needed to raise the strings nearly 5mm.

[Geek99]

I promised you all pictures 

picture 3 taken at #19

 

 

Edited March 23 by Geek99

[Norris]

Talkbass: Some people worry about minutiae, that should spend a lot more time playing.

 

Like @BigRedX says, show me the ramp!

 

Just shim it with a bit of card

[tauzero]

https://www.ebay.co.uk/itm/185779208770

[MrDaveTheBass]

How much "relief" i.e. bend is there in the neck? You might find that tightening the truss rod to straighten the neck will bring the action down significantly.